[ILUG] Question on an encryption system (using OSS)

[Braun Brelin]

Folks,

I'm thinking of putting together an encryption system using some sort of 
either symmetric or public key encryption and I wanted to get some
advice from the list...

Basically, what I want to do is as follows: 

1. I encrypt a file
2. I make this file available via a P2P system like bit torrent. 
3. When someone downloads the file, in order to unencrypt it, they have to 
get a key from me.
4. Since I make it available on P2P, multiple people might download it. Each 
person that wants to read it
has to get a different key so that each key is unique to that person. 

I'm guessing a public key encryption scheme works best here. I'm thinking of 
using GPG to actually perform the encryption and 
generate the keys. 

Is what I want to do basically sound? I.e. am I missing something obvious 
here security-weakness wise?

Thanks,

Braun